Answer:
Step-by-step explanation:
If we had 2 independent samples with population variances unknown and equal and we want to compare the population mean between the both groups, the test statistic will be:
Where
So, the t-student has degrees of freedom
Where and
are the means of the groups,
and
are the size of the samples and
and
are the sample variances.
Answer:
And we can find this probability using the normal standard distribution, excel or a calculator and we got:
And if we convert this into percent we got 84.13% rounded to the nearest percent would be:
84%
Step-by-step explanation:
Let X the random variable that represent the circumferences of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the normal standard distribution, excel or a calculator and we got:
And if we convert this into percent we got 84.13% rounded to the nearest percent would be:
84%